second type I K homology (KH) RNA-binding domain found in the family of MEX-3 RNA-binding proteins
The MEX-3 protein family includes four members, MEX3A/RKHD4, MEX3B/RKHD3/RNF195, MEX3C/ RKHD2/RNF194, and MEX3D/RKHD1/RNF193/TINO. They are homologous of Caenorhabditis elegans MEX-3 protein, a translational regulator that specifies the posterior blastomere identity in the early embryo and contributes to the maintenance of the germline totipotency. Mex-3 proteins are RNA-binding phosphoproteins involved in post-transcriptional regulatory mechanisms. They are characterized by containing two K-homology (KH) RNA-binding domains and a C-terminal RING finger. They bind RNA through their KH domains and shuttle between the nucleus and the cytoplasm via the CRM1-dependent export pathway. The model corresponds to the second KH domain.